Insecticide and method of dehydrating moist materials.



NITED STATES Patented May 9, 1905.

PATENT QFFI AMERICAN AGRICULTURAL YORK, N. Y.

CHEMICAL COMPANY, or NEW INSECTICIDE AND METHOD OF DEHYDRATING MOISTMATERIALS.

SPECIFICATION forming part Of Letters Patent NO. 789,176, dated May 9,1905. Application filed February 26, 1903. Serial No. 145,299.

Elizabeth, in the county of Union, and in the State of New Jersey, haveinvented a certain new and useful Improvement in Insecticides andMethods of Dehydrating Moist Materials;

and I do hereby declare that the following is a full, clear, and exactdescription thereof.

The object of my invention has been to provide a method of dehydratingmoist products, so that they can be shipped or stored and can bemaintained in their original condition and proportions without theprovision of special packing or storing .essols.

The obje of my invention has also been to produce a i insecticide by thesaid method which shed have the above-stated qualities; and to such endsmy invention consists in the IIIBL EOd .of dehydrating moist materialsand in the insecticide hereinafter specified.

My invention in its first part relates to a method of dehydratingmanufactured materials by changing the water which exists in suchmaterials as free water or moisture into the water of combination orcrystallization, where for any reason it is desired to render the saidmaterials dry, and especially where it would be injurious or undesirableto the said materials to dry the same by artificial heat or to allow themoisture to escape by evaporation. To accomplish this desirable result,I mix with the materials to be treated a substance which will take upthe water, as in the form of water. of crystallization or combination,and such substance is preferably such as is inert to the materials beingtreated and such as by its presence will in no way interfere with thepractical use or application of the material beingtreated. Ihave foundthat for this purpose the most desirable substances are those saltswhich combine with Water in the process of crystallization. This methodof dehydration is particularly applicable to those materials which havebeen precipitated from solutions and subsequently filtered, as withpresses, and which, therefore, form a wet paste. When it is necessary touse or apply such materials with water, the salts used for dehydrationshould be soluble in water, and other conditions being fulfilled thosesalts which combine with the largest amount of water, as water ofcrystallization, are the most desirable for this method of dehydration.

As a specific instance of the use of my method and as one which I havefound to be most desirable, I have chosen for illustration itsapplication to arsenate of lead, which has been found to be a mostvaluable insecticide and which has heretofore been shipped as a paste,from the manufacturer to the consumer, the arsenate of lead having beenprecipitated from solutions of soluble lead salts with arsenate of sodaand then passed through filterpresses. This results in a press-cakewhich is wet and which is now shipped in its wet form in water-tightpackages, the paste containing from forty-five to fifty per cent. ofwater. The paste could not be dried without injuring the arsenate oflead, and in shipping it as a paste the water evaporates, so that itsstrength by the time it reaches the consumer has changedfrom that atwhich it was sold by the manufacturer. In applying my invention to thedehydration of this paste I prefer to use sulfate of soda, popularlyknown as Glauber salt, having the formula Nae S04 IOHzO,

which salt crystallizes under ordinary conditions with ten moleculesofwat'er. I first remove the water of crystallization from the sulfateof soda, as by heating the salt to the temperature of centigrade, 'whenthe water of crystallization is driven off. The remaining salt is thenpreferably reduced to a powder and is mixed with the arsenate-ofleadpaste in the proportion of ten parts of dehydrated sulfate of soda totwenty five parts of the paste, although these proportions may vary,according to theamount of water in the paste, the best result beingobtained by adding sufiicient dehydrated sulfate of l the crystallizedsalt N 328041 OHzO. The cryssoda to form with all of the water in thepaste tallized salt N32SO41OH2O melts at about 33 centigrade, and I havefound the-best result to be obtained in mixing the dehydrated sulfate ofsoda with the arsenate-of-lead paste by raising the temperature of themass during the process of mixing to about 35 centi When it is desiredto use the arsenate of lead as an insecticide, the powder is mixed withwater, and the sulfate of soda dissolves, leaving the particles ofarsenate of lead suspended in the water in a desirable form forspraying, the particles being sufiiciently small and uniform so thatthey can be carried by the water and do not accumulate at the bottom ofthe tank of a spraying-machine.

Having thus described my invention, what I claim is 1. The process ofdehydrating apaste containing water and a material insoluble therein,which consists in mixing with said paste,

in quantity suflEicient to dehydrate the same, an anhydrous salt capableof uniting with water but inert toward said insoluble material.

'2. The process of dehydrating a paste containing Water and leadarsenate, which con sists in mixing with said paste an anhydrous sodiumsulfate.-

4. The process of dehydrating a paste containing water and a materialinsoluble therein, which consists in mixing with said paste an anhydroussalt capable of uniting withwater, and maintaining the mass duringmixing at a temperature above the melting-point of the hydrated salt.

5. The process which consists in mixing a paste containing arsenate oflead and Water with anhydrous sodium sulfate, thereby forminga'pulve'rizable mixture of lead arsenate with hydrated sodium sulfate,and maintaining the mass during mixing at a temperature above themelting-point of hydrated sodium sulfate.

6.- An improved insecticide, containing a mixture of lead arsenate and ahydrated salt.

'7. An improved insecticide, containing a mixture of lead arsenate and'hyd rated sodium sulfate.

In testimony that I claim the foregoing I,

have hereunto set my hand.

FREDERI'C J. SMITH. Witnesses:

HENRY J. MILLER, H. N, F. MILLER.

